Evaporator plant



Aug. 31, 1926. 1,598,301

J. MUGLER v EVAPORATOR PLANT I Filed Feb. 8, 1926 2 Sheets-Sheet 1 1NVEN TOR.

444 ATTORNEY.

Aug. 31, 1.926.

J. MUGLER EVAPORATOR PLANT Filed Feb. 8. 1926 2 Sheets-Sheet 2 INVENTOR.BY /7 Patented Aug. 31, 1926.

UNITED STATES JULIUS MUGLER, 0F BERLIN, GERMANY.

EVAPORATOR PLANT.

Application filed. February 8, 1926, Serial No. 86,746, and. in GermanyJanuary 80, 1925.

My invention relates to evaporators and more especially tomultiple-stage evaporators, wherein the evaporating'steam or vapor andthematerial under evaporation passes from one unit to another. Suchevaporators are, for instance, used in sugar factories, where theclarified sugar juice is'concentrated by gradual evaporation in socalledsugar pans to a sirup of a certain density.

The last or ultimate evaporator in the series is usually connected to acondenser in which a vacuum is maintained.

In modern evaporator plants which work with high steam pressure, thecondenser is omitted, the steam in that case being conducted to othersteam consumers, after it has done its work in the evaporators. In suchevaporator plants, because of variations in the steam consumption, thepressure in the last evaporator will either rise above or drop below thedesired point with the result that the final density of the materialunder evaporation varies, and when the pressure rises too high in thelast evaporator, steam must be blown off.

The object of the present invention is to prevent the ill effects ofvarying steam pressure in such plants by the use of automaticallyoperating regulators so as to thereby insure a product of uniformdensity. 'In accordance with this invention, there is provided inaddition to the regular evaporators an additional unit, which mayoperate either as another evaporator or merely as a part through whichthe material under treatment may pass there being provided overflowpipes or by-pass connections for the vapors between the various unitswhich overflow pipes are equipped with automatic regulators so thatsteam of higher pressure of one unit may be supplied to the nextsucceedin units, a further regulator being provided etween theadditional unit and other steam consuming devices. In this way theefficiency of the plant can be kept constant irrespective of anyvariations in the steam consumption, so that at all times a uniformproduct is obtained. However, where the amount 01" the material to beevaporated and the density are not always the same, further .means arerequired to keep the evaporation constant so as to prevent various derees in the density of the final product. 0 this end, I provide in thesteam or vapor pipes special lve, which autom t c lly r gulates thesteam or vapor by means of an automatic density regulator controlled bythe density of the evaporated material.

In the annexed drawing, in which I have diagrammatically shown, by wayof illustration, my invention as applied to a sugar plant, Fig. 1 showsthe arrangement of the evaporator units and the location of theautomatic regulators, Fig. 2 shows an. ar rangement for use when anamount and the density of the material under' treatment vary, Fig. 3 isa detail view of the automatic regulator used in connection with theevaporator units.

According to Fig. 1, the plant comprises the well-known evaporator units1, 2 and 3, adapted to receive the material to be treated, which in theselected example is clarified sugar juice. Fresh steam is supplied tothe heating chamber 0 of the evaporator 1. The hot vapors arising fromthe sugar juice in evaporator 1 pass through the pipe 5 into the heatingchamber C of the evaporator 2, while the hot vapors arising from thejuice in evaporator 2 pass through the pipe 6.int0 the heating chamber Cof evaporator 3. Surplus steam or ivapors pass from the;

respectively to other steam or heat consuming apparatus (not shown). Inaddition to the evaporators 1, 2 and 3 there is provided a further unit4, to the heating chamber-C? of which hot vapors may be supplied atcertain times from evaporator 3 through pipe 7. The pi e 7 is providedwith an automatic regu ator 17 and a similar regulator 16 is provided inthe steam or vapor discharge pipe 8 of the unit 4.

The operation of this plant is as follows: The evaporated sugar juice issuccessively pumped through the pipes 12, 13, 14 from one evaporator tothe next and finall into the additional unit 4, from which it 1sdischarged through the pipe 15 connected to a pump (not shown). 7

If, because of too small a withdrawal of steam or vapors by consumersfrom the pipes 9, 10 and 11, the pressure in the eva orator 3 rises toabove a predetermined point the automatic regulator 17 is caused by therise of pressure to operate to admit steam or vapors to the heatingchamber of the unit 4, which heretofore acted only as a passage for theevaporated sugar juice but now also begins to do work as an evaporator,so that evaporators through the pipes 9, 10 and 11 the total efliciencyofthe plant and thereby also the density of the final product are keptconstant.

Should the pressure in the unit 4 also rise above a predetermined point,due to further lessened steam or vapor consumption through the pipes 9,10 and 11, the automatic regulator 16, like the regulator 17 will beactuated by the excess pressure to let steam or vapors escape from theunit 4 either to a consumer, or a condenser. in case the temperature ofthe unit 4 is so low that the steam or vapor can not be utilized anyfurther. The amount of steam or vapor in that case, however, will beonly a fraction of the steam or vapor wasted in an evaporator plant ofthe usual construction, in which the additional unit for making use ofthe surplus vapors is lacking.

Similar automatic regulators 19 and 20 like those shown at 16 and 17 areprovided in the by-pass connections 19 connecting the pipes 9, 10 and 11in Fig. 1. These latter regulators are provided to permit surplus steamor va or of a unit of a higher stage to be supplied to the unit of alower or succeeding stage, in case the steam or vapor consumption forother steam or vapor consuming devices should decrease while that of thenext succeeding stage increases.

Assuming, for instance, that the steam consumption through the pipe 10connected with the evaporator 2 decreases while at the same time, thoughnot in the same degree, the consumption through the pipe 11 ofevaporator 3 increases, the automatic regulator 20 and under certainconditions also the automatic regulator 19 will be caused by the higherpressure to operate to admit the surplus steam or vapor directly to theevaporator of the next lower stage, from which a greater amount of steamor vapor is drawn to supply other steam or vapor consuming devices. Inthis way, there will always be automatically produced a balance betweenthe several evaporators so that even with varying steam or vaporconsumptions the total etticiency of the plant will remain the same withthe result that a final product of ever uniform density is obtained. Asa matter of course. also the steam supply pipe to the first evaporator1, is equipped with an automatic regulator 18 similar to those shown at16, 17, 19 and 20.

A difl'erent arrangement is shown in Fig. 2, wherein are shown onlythree evaporator units 21, 22, 23 which are connected by the pipes 24and 25 in such a way, that the hot vapors escaping from unit 21 are usedto produce evaporation in unit 22, while the hot vapors from unit 22heat the unit 23. In pipe 25 is provided a throttle 26 which iscontrolled by density regulator 28 provided in the'discharge pipe 27 forthe evaporated material. Said density regulator is so designed that asthe density. of the material decreases it causes the throttle 26 to openautomatically, whereas, if the density increases. the throttle 26 closesso that in the first instance a greater amount of vapors passes into theunit 23, while in the other instance the vapor supply isthrottled. It isself-evident that a similar control can also be used in connection withthe other evaporator units, or, if as in Fig. 1 an additional evaporatorunit is used, in connection with the latter.

In Fig. 3 is shown in detail one type of automatic regulator which maybe used in the arrangement according to Fig. 1.

Reference character 19 designates the connection between conduits 9 and10. Flow of vapor or steam through this connection is controlled by avalve 50 operated by a servomotor 46 which is in turn operated by apilot valve 33, 34, which is in turn operated by 'a relay R which relayis responsive to changes of pressure in conduit 19 ahead of valve 50.Changes of pressure in conduit 19 are transmitted through tube 51 andact upon a bellows 36 which is connected to a lever 52 through theintermediary of a pin 37. Lever 52 carries at one end a battling member38 which is positioned over an opening 41 in a conduit 41 which connectswith the pilot valve housing. Lever 52 is pivoted at 39 and is actedupon by a spring 40, the force of which is opposed to the pressure ofconduit 19* transmitted to bellows diaphragm 36.

The pilot valve is supplied with fluid under pressure by means ofconduit 43. This conduit supplies fluid both to the servomotor and tothe relay. The supply to the relay takes place through a branch conduit43 which contains a restriction 42. The fluid in flowing to the relayflows through a chamber 30 one side of which is formed by a diaphragm 31which is connected to the pilot valve 33, 34. Fluid pressure acts inchamber 30 and is opposed by spring 54. The pilot valve 33, 34 affordsconnection with the servomotor 46 through conduit 45 with either supplyconduit 44 which is connected to conduit 43 or a discharge conduit 55.

The operation of the regulator is as follows:

Assume that the pressure decreases in conduit 19. Lever 52 is thenrocked to restrict outflow through opening 41. This causes a rise ofpressure in chamber 30 which moves diaphragm 31 to the right andconnects conduit 45 with discharge conduit 55. The pressure of fluid onthe upper side of piston 47 is then released and due to the weight 49which acts upon valve 50, piston 47 moves upwardly and valve 50 closes.The pressure is thus returned to normal.

Assume, on the other hand, that the 'pressure increases in conduit 19.This causes a rise of pressure force against bellows 36 4 whichmoves-lever 52 so that bafliing member 38 allows .a greater outflow offluid through opening 41 and from conduit 41. Due to the restriction 42this causes a drop of pressure in chamber 30 which results in a movementof diaphragm 31 to the left and movement of pilot valve 33., 34 to theleft whereby conduit is connected with conduit 44 and pressure fluid issupplied to servomotor 45 causing a downward movement of piston 47whichresults in an opening of valve 50-, thus returning the pressure tonormal. It is thus seen that the valve 50 is so operated that thepressure in conduit 19 in front of the same and therefore the pressurein conduit 9 is maintained constant. Of course, other types ofregulators may be used, and likewise, there may be modifications in theeneral arrangement of parts without any departure from the essence ofthe invention.

I claim: 1. In an evaporator plant, the combination with a plurality ofevaporator units, of an additional unit, and automatically operatedmeans enabling said additional unit to act either as an evaporator ormerely as a discharge vessel for the evaporated product. .2. In anevaporator plant, the combination with a plurality of evaporator units,of an additional unit, a conduit for conducting vapor from the ultimateunit of the plurality to the additional unit, a valve to control flowthrough said conduit and mechanism responsive to pressure of steam insaid ultimate unit for controlling said valve and operating to maintainconstant the pressure in said ultimate unit.

3. In an evaporator plant,'in combination; a conduit system, anevaporator unit in said conduit system connected between a conduit ofrelatively high pressureand a conduit of relatively low pressure, aconnec-' tion extending between said conduit of relatively high pressureand said conduit of relatively low pressure parallel to said evaporator,an automatic valve in said connection and pressure responsive mechanismfor operating said valve to maintain a constant pressure in said conduitof relatively high pressure.

4. In an evaporator plant, iii-combination, a conduit system including aplurality of conduits adapted to carry steam of diiferent pressures andto supply steam to steam consumers, evaporator units coupled be tweensaid conduits, connections extending between said conduits and servingas bypass connections for said evaporator units, and valves in saidconnections operated by pressure of vapor in front of .said valves andacting to maintain the operating pres sure constant.

5.111 an evaporator, in combination, 4 a conduit system including aplurality of conduits adapted to carry steam of difi'erent pressures andto supply steam to steam consumers, evaporator units coupled betweensaid conduits, connections extending between said conduits and servingas by-pass connections forsaid evaporator units, valves in saidconnections operated lay-pressure of vapor in front of said valves andacting to maintain the operating pressure constant, an additionalevaporator unit, and automatically o erated regulating means enablingsaid additional unit to act either as an evaporator or merely as adischarge vessel for the evaporating product.

In testimony whereof I afiix my signature.

- {JULIUS MUGLER.

